Contact lenses are widely used to correct vision. Contact lenses have traditionally been either rigid (hard) or soft.
One important consideration in wearing contact lenses is eye health. Because contact lenses are placed directly on the eye, it is important that they not introduce any unwanted contamination into the eye.
The more commonly used soft contact lenses are designed for use over a specified number of days, and are then to be replaced. For example, many contact lenses are to be used for up to 14 days, after which they are to be disposed of. This routine replacement of soft contact lenses is highly desirable because it is difficult for the patient to sterilize or otherwise adequately clean the lenses, and after use over a period of days, they have a tendency to build up contamination.
A contact lens wearer must have a container or receptacle to store a currently used set of contact lenses when they are not being worn, such as when the wearer is sleeping. The storage container should enable the wearer to store the lenses in a suitable hydrating and anti-microbial solution and thus must be resealable. A typical contact lens storage case has two compartments that are marked or fashioned in some way in order to differentiate the right and left compartments. This is necessary because some wearers need a different prescription to correct the vision in their left eye compared to the prescription to correct the vision in their right eye. The typical storage cases thus provides a means for the user to remember which contact lens is made for which eye once lenses have been removed, as it is difficult to distinguish one contact lens from the other with the naked eye.
Soft contact lenses are often sold in multiple packages of lenses to supply the wearer with enough lenses to last for six months or a year. A typical package has a “blister” molded out of high quality polypropylene, with a contact lens and solution needed to keep it hydrated retained in the blister by a film which is sealed over the blister and secured to the margin area around the blister.
One problem that many wearers face is keeping track of the different lenses and knowing which eye they are for. The lenses are typically supplied by the manufacturer with a listing of the parameters (such as the power, diameter, base curve, etc.), but unless the dispensing optometrist indicates which eye they are for, the wearer must ascertain this for themselves. Even if the dispensing optometrist designates whether the lens is for a left or right eye on an outer package, individual contact lens packages do not contain that information. Additionally, once the outer packages have been opened, they are usually not fully resealable, and lens packages may fall out and be mixed up with others from another outer package when stored away. Furthermore, a majority of wearers have different prescriptions for each eye, but the differences are not great. Thus, if the wearer gets the lenses mixed up, it may take wearing the lenses for a while before the wearer realizes his or her vision is not as good as it should be and figures out that the lenses need to be switched.
Another problem that has not been heretofore addressed is the need to replace contact lens storage cases frequently. Even though many wearers realize that they need to dispose of lenses after the recommended wearing period, they do not realize that their lens storage case can become contaminated. Over time these storage cases can build up contaminants and become a breeding ground for microbes, even though the lens case is rinsed out each morning after the contact lenses are removed and placed in the wearer's eyes.
Some prior art references disclose contact lens packages that are suggested for use as the lens storage case. However, none of these designs have found widespread acceptance, and none are used by major manufacturers of contact lenses at the present time. Presumably, this is because the designs have been discovered to be impractical. For example, U.S. Pat. No. 5,224,593 discloses a combination lens shipper/lens case. However, it has several drawbacks. First, the bottom of the shipper/case is merely heat sealed on to the rest of the case, and it may gradually work its way loose over time. More importantly, the inside of the case is in the form of a cylinder, with a flat bottom which will make retrieving the lens quite difficult. Most contact lens cases have a concave bottom to facilitate lens removal.
Japanese Patent publication 001-255499 discloses another contact lens package that is suggested for use as a lens storage case. The package includes a cover that fits down inside or depression. The cover and the fringe part surrounding the depression is then covered by a sheet film when the sheet film is peeled off, the cover sticks to it and opens. The lens can then be removed. Supposedly the cover can be placed back in the depression to reseal the blister. This design has several drawbacks. Most importantly, the cover is smaller than the opening. As a result, it has to fit inside of the depression. As a result, it would be very difficult to make the cover exactly the right size so that it could provide a leak-proof seal, especially if the parts were mass produced.
Another problem faced by contact lens wearers is keeping track of how long a current pair of lenses has been worn. Some people favor daily disposable lenses for this reason. However, most soft lens wearers use lenses designed for replacement after two weeks or one month. For many people this period of time goes by with no good way to keep track of it. As a result, a person must either make a note on a calendar, or somewhere else, and constantly refer to the note, or they lose track of when they last started using the current pair of lenses and either dispose of them earlier than necessary or later than they should. This problem is exacerbated if the wearer tears or damages a lens during its normal wearing period and has to restart with a fresh lens and now monitor two wearing schedules.
Thus it can be seen that even though the benefits of soft contact lenses outweigh these problems, and their acceptance continues to grow, it would be of great benefit if one or more of these problems could be solved.